Preview & Rendering
Frame Preview
The preview panel shows a single rendered frame of your video at the current timeline position. It activates once you have both an audio file and a subtitle file loaded (and FFmpeg configured).
Navigating the Timeline
Timeline scrubber — The slider at the bottom of the preview panel lets you drag to any point in the video. The current timestamp and frame number appear in the top-right corner.
Jump buttons on the right side give you quick access to key positions:
| Button | Action |
|---|---|
| Start | Jump to the first frame (0:00) |
| Previous Cue | Jump to the previous subtitle's start time |
| Current Cue | Jump to the active subtitle's start time |
| Next Cue | Jump to the next subtitle's start time |
| End | Jump to the last frame |
TIP
Use the cue jump buttons to quickly check how each lyric line looks. Step through your entire video cue-by-cue to spot any styling issues.
Preview States
The preview panel shows different messages depending on the current state:
- "FFmpeg is not configured" — Set up FFmpeg from the menu or the banner link.
- "Pick audio and subtitle files" — Load both files in the Project Setup panel.
- "Preview paused while a full render is active" — The preview pauses during rendering to free up resources.
- "Rendering preview frame..." — A frame is being generated.
Render Settings
Configure render settings in the Output / Render and Video sections of the Project Setup panel.
Video Dimensions
Choose a Size preset for common resolutions:
| Preset | Resolution |
|---|---|
| 4K | 3840 x 2160 |
| 2K | 2560 x 1440 |
| 1080p | 1920 x 1080 |
| 720p | 1280 x 720 |
| 1024 Square | 1024 x 1024 |
| Custom | Enter any width and height (minimum 16px) |
Frame Rate
Choose a FPS preset or set a custom value:
| Preset | FPS |
|---|---|
| 15 fps | 15 |
| 20 fps | 20 |
| 30 fps | 30 |
| 60 fps | 60 |
| Custom | Any value (minimum 1) |
Encoding
Choose the output format:
| Encoding | Format | Codec |
|---|---|---|
| x264 | MP4 | H.264 |
| x265 | MP4 | H.265 (HEVC) |
| WebM | WebM | VP9 video + Opus audio |
Quality
Each encoding has three quality levels. Lower CRF values produce higher quality at larger file sizes.
x264 (H.264):
| Preset | CRF | Notes |
|---|---|---|
| Smaller file | 28 | Faster encoding |
| Balanced | 23 | Good default |
| High quality | 18 | Slower encoding |
x265 (H.265):
| Preset | CRF | Notes |
|---|---|---|
| Smaller file | 32 | Faster encoding |
| Balanced | 28 | Good default |
| High quality | 23 | Slower encoding |
WebM (VP9):
| Preset | CRF | Notes |
|---|---|---|
| Smaller file | 38 | Faster encoding |
| Balanced | 32 | Good default |
| High quality | 28 | Slower encoding |
Render Threads
Controls how many Chromium workers render frames in parallel. More threads = faster rendering, but more memory usage. Start with the default and increase if you have RAM to spare.
Rendering a Video
- Configure your files, scene, and settings.
- Click Render MP4 (or Render WebM) at the bottom of the Project Setup panel.
- A progress dialog appears showing:
- Current rendering phase (preparing, rendering, muxing)
- Progress bar and percentage
- Current FPS and ETA
- Click Cancel Render at any time to abort.
- When complete, your video is saved to the output path you chose.
Render Phases
| Phase | What happens |
|---|---|
| Preparing | Audio analysis and component pre-computation |
| Rendering | Each frame is rendered by Chromium workers |
| Muxing | Frames and audio are combined into the final video file |
WARNING
The preview panel pauses during a full render. It resumes automatically when the render completes or is cancelled.